• Seedling density and the regeneration mechanisms of five tree species,
Anogeissus leiocarpa, Combretum aculeatum, Combretum micranthum, Combretum
nigricans, and Pteleopsis suberosa were investigated in
relation to latitudinal gradient across the Sahelo-Sudanian zone of West Africa.

• Data were collected on 461 quadrats (2m × 5m) laid out every 30 m on transect lines
through Combretaceae communities at four latitudinal positions. Regeneration mechanisms
were determined by excavating the below ground root system and assessing basal and aerial
sprouts.

• The results showed a significant species × latitudinal position effect on the total
density of seedling populations, and the density of single- and multi-stemmed individuals
(p < 0.001). C. aculeatum and C.
micranthum were abundant in the North-Sahelian sector, C. nigricans
and P. suberosa in the Sudanian sector and A. leiocarpa
across a wide range from the South-Sahelian to South-Sudanian sectors. In
general, 58% of the seedlings were regenerated asexually (as coppice, water sprout, layer,
and root sucker) while 42% were sexual recruits (as true seedling and seedling sprouts).
The proportion of vegetatively propagated seedlings increased with increasing latitude for
all species except C. micranthum, for which a clear decreasing trend was
observed. The relative importance of the different regeneration mechanisms varied among
species: seedling sprouts were important for A. leiocarpa, C. aculeatum
and C. nigricans, coppice for C. micranthum and
sucker for P. suberosa

• The significant interaction observed between species and latitudinal position
highlights the importance of accurate species-site matching to ensure successful
restoration of degraded areas in the Sahelo-Sudanian zone. Inter-species differences in
regeneration mechanism could be related to their biology and ecological adaptation to the
site-specific biotic and abiotic factors.